US1419562A - Modulator or detector - Google Patents

Modulator or detector Download PDF

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Publication number
US1419562A
US1419562A US327331A US32733119A US1419562A US 1419562 A US1419562 A US 1419562A US 327331 A US327331 A US 327331A US 32733119 A US32733119 A US 32733119A US 1419562 A US1419562 A US 1419562A
Authority
US
United States
Prior art keywords
modulator
circuit
waves
output
devices
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US327331A
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English (en)
Inventor
Ralph V L Hartley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Western Electric Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL8808D priority Critical patent/NL8808C/xx
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US327331A priority patent/US1419562A/en
Priority to DEB95875D priority patent/DE365607C/de
Priority to FR23528A priority patent/FR23528E/fr
Priority to GB26901/20A priority patent/GB151928A/en
Application granted granted Critical
Publication of US1419562A publication Critical patent/US1419562A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/52—Modulators in which carrier or one sideband is wholly or partially suppressed
    • H03C1/54—Balanced modulators, e.g. bridge type, ring type or double balanced type

Definitions

  • the present invention relates to a simplified circuit for the control of one wave by another for signaling or other purposes.
  • Circuit arran ements of this general type are commonly known in the art as modu ators, demodulators or detectors, according to the use to which they are put.
  • the invention relates particularly to a novel form of balanced modulator or detector in which preferably a pair of three electrode discharge devices are connected so as to emphasize the production of certain wave components and to neutralize the production of other components.
  • the two discharge devices are to be so connected relative to the impressed waves as to cause the wave of unmodified frequency that is transmitted by one of the discharge devices to be neutralized by that transmitted by the other. If the input wave '0, impressed on one electron discharge device is reversed in sign relative to that impressed on the other, that is ifthe two waves have a phasedifi'erence 0 180, and the output currents are then added, the desired result is accomplished as is indicated in the following equation, in
  • a modulator according to the invention is shown situated between a work circuitl, for any desired purpose, and wave sources which are indicated by way of example. as a. source 2 of sustained high frequency waves and a source of volce current produced in the circuit 3 for modulating the high fre uency or carrier waves from source 2.
  • source 2 is preferably near but higher than the highest essential voice fre uency in the system shown, al though this is not necessary if the waves produced in circuit 3 are not to be speech waves.
  • Both the carrier or high frequency Waves from source 2 and the speech waves are impressed on the same circuit 4, which contains potentiometer resistances 5 and 6 for permitting adjustment of the respective amplitudes of the waves so impressed.
  • Circuit 1 also contains a coil 7 by which it is coupled to the modulator through the medium of coil 8.
  • the modulator comprises the two discharge devices or electron tubes 9 and 10, which may be of well known construction and which should, for the best operation. be carefully chosen to have so far as possible identical characteristics, as has already been pointed out in connection with the equations above given.
  • the discharge devices or electron relays comprise preferably highly evacuated enclosures containing the respective heated filaments 11, 12, the respective anodes 13, 1 1, and the respective grids or impedance controlling elements 15, 16, the filaments being heated by current from the source 17 through regulating resistances shown.
  • the grids 15 and 16 are connected respectively to the opposite terminals of coil 8 and the filaments are connected in common to the mid-point of coil 8. Voltages induced in coil 8 from coil 7, therefore, ailect the potential of the grids oppositely with respect to their common filament potential.
  • the battery 18 is shown for fixing the normal potential of the grids.
  • Across the terminals of coil 8 is a resistance 19 having a sliding contact 20 connected to the common filament connection.
  • a variable condenser 21 is also shown in shunt of one-half of the coil 8.
  • the purpose of elements 19, 20 and 21 is to compensate for any difierences in the two halves of coil 8 and to secure a more perfect balance of the two sides of the circuit with respect to the common filament terminal which is usually grounded.
  • Howevemelements 19, 20 and 21 are not essential to the present invention and may be omitted particularly where the coil 8 is to a high degree symmetrical with respect to the .common filament terminal.
  • the anodes or plates 13 and 14 are connected at point 22 directly together by means of a conductive connection of suhstantially zero reactance and connection is made from this point to the common filament trrminal through two circuit branches.
  • ()nc of the two branches includes the choke coil 23 and space current source 24, and substantially a constant current branch, while the other circuit branch includes the large condenser 25 and the output primary coil 26 and serves as a path for the variable wave components.
  • the latter branch is coupled to coil 27 in the work circuit 1.
  • connection bctween the anodes 13 and 14 contains no coils or condensers and is, therefore, non-reactive.
  • the invention may conveniently make use of a double electron discharge device having one heated filament 28, as shown in Fig. 2, two grids 29, 30, and two plates 31, 32, which may be one piece of metal extending from one side oi one grid around to the opposite side of the other grid.
  • a metallic plate of this type or by connecting the two plates or anodes together within the coutainer itself, which is usually a glass bulb, one less lead need be taken through the hull) than if the anodes were connected externally oi the bulb.
  • the external connections indicated are substantially the same as those in F ig 1.
  • the invention has been described as a modulator, but it may equally well be used as a demodulator or a detector in case the wave in circuit 3 is a modulated wave to be detected. Tn either case it is the usual pracw tice to include suitable selective circuits in the work circuittor selecting the desired wave component, but such circuits being well known and forming no part of the present;
  • a balanced modulator comprising two similar discharge devices each having a cathode, a control element and an anode, said cathodes being connected directly together, acircuit for causing equal and opposite instantaneous variations of the potentials of said control elements by a wave to be-modulated and a modulating wave, and a single substantially non-reactiveconnection between said circuit and said cathodes.
  • a balanced modulator or demodulator comprising two similar electron discharge tubes each having a cathode, an impedance controlling element and an, anode, said cathodes being connected together. and said anodes being connected together, an input 'circuit individual to each tube connected between its impedance controlling element and said cathodes, and a common output circuit for said tubes,'one terminal being connected to both cathodes and .the other terminal to both anodes.
  • a balanced modulator or demodulator comprising two similar electron discharge 5 tubes each having a cathode, an im edance controlling element and an ano e, said cathodes'being connected together and said waves in opposite phase upon said input circuits.
  • balanced modulator or demodulator comprising two slmilar electron tubes each having input andoutput terminals, a plurality of sources of waves for said modulator or demodulator, connections for impressing said waves on the input'terminals of each tube simultaneously in opposite phase,.,the respective output terminals of said tubes being connected conductively together, and
  • terminals bein connected respectively to said conductive y connected output terminals.
  • a balanced modulator or demodulator comprising a pair of three-electrode d1s-' charge devices, two of the electrodes of one device being non-reactlvely connected respectively to the corresponding electrodes of the other device, an output circuit commonto both devices connected between the respective non-reactivel connected electrodes, a
  • a modulator or demodulator comprising a pair of similar electron discharge devices each having a cathode, a controlling element and an anode, circuits or substantially zero reactance connecting said cathodes together and said anodes together, sources of waves for said modulator or demodulator,
  • a modulator or demodulator comprising a source of direct current, a pair of asymmetrically conducting devices connected in parallel with each other and in series with said source, impedance'controlling elements for said devices, sources of waves each acting oppositely-upon said control elements to vary the impedance of said devices comple- 9 'mentally, and an output'circuit for said modulator or demodulator connected in series with said devices.
  • a modulator or demodulator comprising a source of direct current, a pair of asymmetrically conducting devices connected in parallel with each other and in series with said source, impedance controlling ele-' ments for said devices, sources of waves each acting op ositely upon said control elements to vary t e impedance of said devices complementally, and an output circuit for said ioo modulator or demodulator connected in series with said devices and in parallel with said source of direct current.

Landscapes

  • Microwave Tubes (AREA)
  • Selective Calling Equipment (AREA)
  • Circuit For Audible Band Transducer (AREA)
US327331A 1919-09-29 1919-09-29 Modulator or detector Expired - Lifetime US1419562A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL8808D NL8808C (enrdf_load_stackoverflow) 1919-09-29
US327331A US1419562A (en) 1919-09-29 1919-09-29 Modulator or detector
DEB95875D DE365607C (de) 1919-09-29 1920-09-12 Verfahren zur UEbertragung von Toenen vermittels elektrischer Wellen
FR23528A FR23528E (fr) 1919-09-29 1920-09-16 Procédé et appareil de modulation pour la signalisation électrique à haute fréquence
GB26901/20A GB151928A (en) 1919-09-29 1920-09-21 High frequency electric signalling

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US327331A US1419562A (en) 1919-09-29 1919-09-29 Modulator or detector

Publications (1)

Publication Number Publication Date
US1419562A true US1419562A (en) 1922-06-13

Family

ID=23276125

Family Applications (1)

Application Number Title Priority Date Filing Date
US327331A Expired - Lifetime US1419562A (en) 1919-09-29 1919-09-29 Modulator or detector

Country Status (5)

Country Link
US (1) US1419562A (enrdf_load_stackoverflow)
DE (1) DE365607C (enrdf_load_stackoverflow)
FR (1) FR23528E (enrdf_load_stackoverflow)
GB (1) GB151928A (enrdf_load_stackoverflow)
NL (1) NL8808C (enrdf_load_stackoverflow)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE944560C (de) * 1953-05-31 1956-06-21 Siemens Ag Doppelroehrenschaltung mit Unterdrueckung von durch die Kruemmung der Roehrenkennlinien hervorgerufenen Stoerungen
NL262119A (enrdf_load_stackoverflow) * 1960-03-15

Also Published As

Publication number Publication date
FR23528E (fr) 1921-11-30
NL8808C (enrdf_load_stackoverflow)
DE365607C (de) 1922-12-18
GB151928A (en) 1921-03-10

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